Braised Halibut with Leeks and Mustard

Why this recipe works:

When it comes to methods for cooking fish, braising is often overlooked. But this approach, which requires cooking the fish in a small amount of liquid so that it gently simmers and steams, has a lot going for it: As a moist-heat cooking method, braising is gentle and thus forgiving, all but guaranteeing moist, succulent fish. Plus, it makes a one-pot meal since the cooking liquid becomes a sauce, and it’s easy to add vegetables to the pan to cook at the same time. We chose halibut for its sweet delicate flavor and firm texture that made for easier handling. Because the portion of the fillets submerged in liquid cooks more quickly than the upper half that cooks through in the steam, we cook the fillets for a few minutes in the pan on just one side and then braise the fillets parcooked side up to even out the cooking. Vegetables that held their shape but cooked through quickly worked best. For the cooking liquid, wine supplemented by the juices released by the fish and vegetables during cooking delivered a sauce with balanced flavor and just the right amount of brightness. Butter gave it some much-needed richness and the right velvety texture.

Serves 4

We prefer to prepare this recipe with halibut, but a similar firm-fleshed white fish such as striped bass or sea bass that is between 3/4 and 1 inch thick can be substituted. To ensure that your fish cooks evenly, purchase fillets that are similarly shaped and uniformly thick.

Ingredients

• 4 (6- to 8-ounce) skinless halibut fillets, 3/4 to 1 inch thick
• Salt and pepper
• 6 tablespoons unsalted butter
• 1 pound leeks, white and light green parts only, halved lengthwise, sliced thin, and washed thoroughly
• 1 teaspoon Dijon mustard
• 3/4 cup dry white wine
• 1 teaspoon lemon juice, plus lemon wedges for serving
• 1 tablespoon minced fresh parsley

Instructions

1. 
   
   1. Sprinkle fish with 1/2 teaspoon salt. Melt butter in 12-inch skillet over low heat. Place fish in skillet, skinned side up, increase heat to medium, and cook, shaking pan occasionally, until butter begins to brown (fish should not brown), 3 to 4 minutes. Using spatula, carefully transfer fish to large plate, raw side down.
   2. Add leeks, mustard, and 1/2 teaspoon salt to skillet and cook, stirring frequently, until leeks begin to soften, 2 to 4 minutes. Add wine and bring to gentle simmer. Place fish, raw side down, on top of leeks. Cover skillet and cook, adjusting heat to maintain gentle simmer, until fish registers 135 to 140 degrees, 10 to 14 minutes. Remove skillet from heat and, using 2 spatulas, transfer fish and leeks to serving platter or individual plates. Tent loosely with aluminum foil.
   3. Return skillet to high heat and simmer briskly until sauce is thickened, 2 to 3 minutes. Remove pan from heat, stir in lemon juice, and season with salt and pepper to taste. Spoon sauce over fish and sprinkle with parsley. Serve immediately with lemon wedges.
   
   
   

Technique

Secrets to Perfect Braised Fish

While braising fish offers a lot of appeal, it does have a downside: Because the fish is partially submerged in a small amount of cooking liquid, you are essentially half steaming, half simmering it. In tests comparing steaming halibut to completely submerging it in water and simmering it, we found that steaming took 57 percent longer. Why? For the fish to cook, molecules have to transfer their energy to the food through direct contact. Not only does simmering water generate only a small amount of steam, but many of those steam molecules condense on the lid rather than hitting, and transferring their energy to, the fish. Thus, far more molecules come in contact with the food in the simmering water than they do in the steam, making simmered food cook faster.
So it’s no surprise that in our early tests for braised fish fillets, by the time the steamed portion had cooked through, the simmered portion had overcooked.
To address this discrepancy, we parcook one side of the fillets by sautéing them briefly, and then we arrange them atop a bed of wine and vegetables, raw side down, for the braise. This gives the upper portion that cooks through more slowly by steam a jump start. The result: perfectly moist, evenly cooked fillets.

READY: Give one side of the fish a head start by cooking it gently in butter.

SET: Transfer the parcooked fillets to a plate, raw side down, while you prepare the braising liquid.

BRAISE: Cook the fish, raw side down, on a bed of vegetables and wine. The parcooked side steams more slowly, and the raw side simmers more quickly.